Within the field of the automotive aftermarket, there are numerous parts that are considered to be “non-serviceable” items. In such cases, a new part is purchased at a substantial cost to the end user. In the field of automatic transmissions, one such common device is the solenoid module assembly that controls hydraulic flow and pressure within the transmission. A typical solenoid module includes a hydraulic manifold and one or more electromechanical solenoids. The hydraulic manifold contains numerous fluid circuit passages that hydraulically communicate with the solenoids. The electromechanical solenoids control either the flow (on/off control) through the passages or regulate pressure within the passages. Typically, the solenoids are electrically connected to a terminal housing that provides for a removable connection to a wire harness, allowing for communication to the powertrain control unit (PCU).
One such apparatus is described in U.S. Pat. Nos. 4,678,006 and 4,783,049. In the disclosure, a device including five electrically actuated solenoid assemblies are situated on an aluminum manifold block including multiple fluid passageways. The connections for the solenoids includes round pins that extrude upwards through a circuit board and are soldered into place. The circuit board consists of strips of copper forming circuit tracks that are further encased in plastic, herein generally referred to as a circuit board assembly (CBA). The CBA interconnects to a terminal connector providing communication through a wire harness to the PCU. This particular solenoid module is used in the Ford E4OD and 4R100 automatic transmission since 1989. It has several well known failure modes and is a common replacement item. These new modules typically cost $150-200 to the end user.
Another such apparatus is described in U.S. Pat. No. 6,056,908. The disclosure is for a method of producing a solenoid module assembly with similar features to the '006 and '049 patents. In this design, an overmolded circuit assembly is described where circuit tracks are formed from strips of beryllium copper and overmolded with plastic. Furthermore, connection with the solenoids and terminal connection is preferably through the use of M shaped slots in which the solenoid terminals are pressed through, creating a friction type connection. The connection between the solenoid terminal and circuit track is made by the pressure generated from the displaced slot. This forms a one-way barbed type connection that prevents easy removal of the circuit track. This may prevent the slot from “backing off” the solenoid terminal. However, this connection style inhibits the removal of the circuit assembly for servicing. One feature of this style of connection is that rectangular pins are used.
A variation of the '908 design is the solenoid module 50P produced by Bosch that is used in the 2002-2003 Ford 5R55W, 2004-up 5R55S and the 1999-up 5R55N automatic transmissions. This module is shown in FIG. 1. This solenoid module has high failure rates, similar to the E4OD/4R100 solenoid module described in the '006 and '049 patents. This solenoid module costs the end user between $200-300. There has been extensive interest in rebuilding this module as generally the failure is localized to an individual solenoid (56P) (57P) (58P) or a broken circuit track (71P) within the assembly. However, the major obstacle has been the CBA that cannot be easily removed in one piece for reuse.
The CBA 70P includes multiple circuit tracks 71P that are placed within two plastic housings 72P and 74P that are snapped together, sandwiching the circuit tracks into place. During the removal process, the circuit assembly 71P flexes, which releases the snapped connections between the two housings 72P and 74P, and results in the circuit tracks to fall out of location.
FIG. 2 is a picture of the 5R55 module from the CBA side. FIG. 3 is a picture of a CBA without the top housing half, exposing the internal circuit tracks 71P. FIG. 4 is an enlarged picture of the terminal connection area, which shows spring-loaded frictional fits in the form of the barbed, press-fit connections 78P. In this figure, the rectangular configuration of the pins 77P can be seen clearly. FIG. 5 is a picture of typical results when attempting removal of the CBA. In this figure, it can be seen that the circuit tracks have snapped out of position, and the barbed connection 78P are no longer in reliable electrical communication with the internal circuitry of circuit tracks 71P. FIG. 6 is a picture of the module 50P after removal of the CBA 70P and manifold 52P. FIG. 7 is a picture of a failed circuit track within the assembly.
What is needed is a reliable, low cost method to rebuild electro-hydromechanical assemblies. Various embodiments of the present invention do this in novel and nonobvious ways.